Manufacturing method of polarizing property electrode for electrical double layer capacitor, and manufacturing method of electrode sheet for electrical double layer capacitor

Abstract

In an electrode drying process in which the electrode is molded in a sheet shape by kneading activated carbon powder, a binding material and an organic solvent for lubrication and a polarizing property electrode is formed by heating and removing the organic solvent for lubrication in the molded electrode, the organic solvent for lubrication included in the electrode is removed in a state in which the above electrode is widened in the sheet shape. In a manufacturing method of an electrode sheet for the electrical double layer capacitor, continuous drying and vacuum drying are performed in a drying process.

Description

BACKGROUND OF THE INVENTIONThe present invention relates to a polarizing property electrode for an electrical double layer capacitor and its manufacturing method.Further, the present invention relates to a manufacturing method of an electrode sheet for an electrical double layer capacitor, and particularly relates to the improvement of a drying process for drying the electrode sheet.The electrical double layer capacitor has a large capacity of a farad class and is excellent in charge and discharge cycle characteristics. Therefore, the electrical double layer capacitor is used in uses such as a backup power source of an electric device, a battery mounted to a car, etc.This electrical double layer capacitor is constructed by arranging a pair of polarizing property electrodes, a separator arranged between the pair of polarizing property electrodes, and an electrolyte. The polarizing electrodes separated by the separator are constructed so as to respectively act as an anode and a cathod...

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Benefits of technology

In accordance with such a manufacturing method of the polarizing electrode, the organic chemical compound such as the organic solvent for lubrication, etc. in the electrode drying process is removed in the state in which the sheet for an electrode is widened approximately in the plane shape. Accordingly, a scattered object (evaporated object) of the above organic chemical compound does not easily stay within an atmosphere in the vicinity of the sheet surface for an electrode. As a result, the removing efficiency of the organic chemical compound from the sheet for an electrode is improved. Then, the amount of the organic chemical compound left within a minute hole of the activated carbon powder can be reduced. Accordingly, there is no fear that the formation of the electrical double layer using the adsorption of an electrolytic ion with respect to the activated carbon powder is prevented. Thus, the electrical double layer is sufficiently formed within the minute hole of the activated carbon powder, and the polarizing property electrode having small diffusion resistance between the activated carbon powder and the electrolyte is obtained.

In accordance with such a manufacturing method of the polarizing electrode, the organic chemical compound such as the organic solvent for lubrication, etc. in the continuous electrode drying process is removed until the organic chemical compound has a concentration of 800 ppm or less (with respect to the weight of the electrode sheet). Accordingly, subsequent cell drying is easily performed and the amount of the organic chemical compound left within the minute hole of the activated carbon powder can be reduced. Therefore, there is no fear that the formation of the electrical double layer using the adsorption of the electrolytic ion with respect to the activated carbon powder is prevented. Thus, the electrical double layer is sufficiently formed within the minute hole of the activated carbon powder, and the polarizing property electrode having small diffusion resistance between the activated carbon powder and the electrolyte is obtained.

In accordance with such a polarizing property electrode for the electrical double layer capacitor, since the concentration of the organic chemical compound included within the polarizing property electrode is set to 800 ppm or less (with respect to the weight of the sheet for an electrode), the amount of the organic chemical compound left within the minute hole of the activated carbon powder is small, and there is no fear that the formation of the electrical double layer using the adsorption of the electrolytic ion is prevented. Thus, the electrical double layer is sufficiently formed within the minute hole of the activated carbon powder, and the diffusion resistance between the activated carbon powder and the electrolyte is reduced.

When the concentration of the organic chemical compound exceeds 800 ppm (with respect to the weight of the sheet for an electrode), it is very difficult to usefully remove the organic chemical compound of the electrode body by heating and pressure reduction in the manufacture of the electrical double layer capacitor using such an electrode. As a result, it is not preferable since the formation of the electrical double layer using the adsorption of the electrolytic ion is prevented, and the diffusion resistance between the activated carbon powder and the electrolyte is increased, and electrode performance as the polarizing property electrode for the electrical double layer capacitor is reduced.

Further, the present invention is made in consideration of the above situation, and its object is to provide a manufacturing method of the electrode sheet for the electrical double layer capacitor able to set the remaining amount of moisture, etc. in the electrode sheet to a very low value and causing no electrolysis of water at the actual using time and able to maintain durability and reliability for a long period.

Therefore, when the heating wind is used in the drying process of the electrode sheet, it is also very important to strictly control the impurity amount mixed into this heating wind so as to secure the durability and reliability of the electrical double layer capacitor for a long period.

Problems solved by technology

Accordingly, a scattered object (evaporated object) of the above organic chemical compound does not easily stay within an atmosphere in the vicinity of the sheet surface for an electrode.

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